wrote:PC Chips M919 has a single VLB slot, 3 PCI slots, and supports EDO. v3.4 has a fairly recent BIOS -- May or June 1996. I use this MB on my testbed.
Sorry, I should have been more specific in my enquiry. When I asked about EDO RAM being supported on a UMC 486 mobo that has VLB slot(s), I really meant no PCI at all. So, just ISA and VLB.
wrote:wrote:PC Chips M919 has a single VLB slot, 3 PCI slots, and supports EDO. v3.4 has a fairly recent BIOS -- May or June 1996. I use this MB on my testbed.
Sorry, I should have been more specific in my enquiry. When I asked about EDO RAM being supported on a UMC 486 mobo that has VLB slot(s), I really meant no PCI at all. So, just ISA and VLB.
I don't know, but I'd say chances of a VLB-only board supporting EDO are pretty slim.
Many VLB boards don't even support 3.3v CPU's, only 5v. When EDO emerged, PCI was well under way to replacing VLB already.
There "could" be VLB-only boards supporting EDO, but I suppose it won't be many.
I am generally inclined to agree with Tetrium. I have had a 486 motherboard with 3 VLB slots (no PCI), 4 72-pin SIMM slots, and a working PS/2 mouse port. It was the only PS/2 mouse capable non-PCI 486 motherboard I had ever seen. I'm sorry now that I let it go. I did not try EDO RAM in it, nor did I take note of the Northbridge part numbers. Even PCI-based 486 boards with a working PS/2 mouse port were rather rare. They typically had the UM8663 Super-I/O chip w/UM8667 serial driver chips as opposed to the UM8670 Super-I/O chip. The Biostar MB-8433UUD has a working PS/2 port and perhaps the Shuttle-Hot 433 v.4.0 but no VLB.
Why are you looking for non-PCI based VLB motherboard? Have you noticed instability when VLB is mixed with PIC? There are a few PCI/VLB motherboards out there with 2 or 3 VLB slots. Does anyone know why they bothered to make 3xVLB motherboards? As far as I know, VLB was only for video cards and harddrive/floppy cards, i.e. for IDE or SCSI.
When VLB was brand new, it was basically VLB or only ISA, and since manufacturers wanted to sell as many boards as possible, they perhaps just put 3 VLB slots to make it sound better?
My guess for wanting a VLB-only board is to avoid having the VLB slots bridged together with the PCI slots?
Good luck determining which are bridged and if they are even better as a result. I'm not sure that there are quality VLB and PCI 486 chipsets. Even the Intel PCI chipsets suck.
Perhaps even more important is board quality though. Not sure if there are exceptional boards either. 😁
I have a feeling that the EISA boards are where most quality was.
Good luck determining which are bridged and if they are even better as a result. I'm not sure that there are quality VLB and PCI 486 chipsets. Even the Intel PCI chipsets suck.
Why do you think that all 486 PCI implementation suck?
Because I haven't heard of or used a good one. They tend to have horrible busmaster DMA performance (as in high CPU utilization and low bandwidth) and funky IRQ issues. Part of it is simply due to them being early PCI designs and because the boards are often low quality. Their age also means that they are only PCI 2.0 compliant which is not good for compatibility.
It's not much different with the early Pentium chipsets but nobody talks about or uses them because they are not worth bothering with. I'm talking hardware like Intel's 430NX and 430LX.
Here's a retro info post from Usenet. What's also scary is how you also have to watch for the revisions that aren't super buggy because they are even worse. 😉
Here follows a brief summary of PCI chipsets. I've tried to keep it accurate, but if you spot any flaws please feel free to cor […]
Here follows a brief summary of PCI chipsets. I've tried to keep it
accurate, but if you spot any flaws please feel free to correct me, and
if you have details on other chipsets, please feel free to let me know
about them. I've included information at the end of this list to help
people ID the chipset (assuming they have an Intel chipset on their
motherboards). Where I know for sure that they do, I have indicated
that a chipset will use parity RAM. PCI Vendor IDs first in HEX then in
decimal appear in brackets beside the chipset names.Usefull numbers: (8/27/95)
---------------ALI: (408) 764-0644 (sales)
Intel: (800) 628-8686 (tech. support)PART ONE: 80486 Chipsets
-------------------------1) The Aries Chipset (Intel: 8086/32902) (8/28/95)
-----------------This is a chipset made by Intel for 80486-based machines, and used in
boards (such as the Asus AVP4) where PCI and VL buses are to coexist.
Unlike the Contaq chipset below, the Aries chipset implements PCI using
a PCI to CPU bridge, and the VL bus is attached to this. This allows
for full PCI performance, though I don't know what effect it has on VL
(which likely will run no faster than the 33 MHz at which PCI 2.0 runs).
The chipset has apparently been through at least two revisions, at least
one of which has problems with protected-mode code and zero wait-state
cache operation. (This may be worked around via the system BIOS by
setting the cache so that it uses 1 wait state for its operations.) In
addition, this chipset does not support PCI - PCI bridges, as the
Adaptec 3940 does not work with it.2) The Contaq Chipset (Contaq: 1080/4224) (8/27/95)
------------------The Contaq 82C599 is paired with one of their 486VL chipsets (82C596 or
82C597) and bridges directly from the 486 CPU to the PCI bus.
Paraphrased from the Contaq spec.:The 82C596 system controller provides the CPU interface, VESA bus
interface, ISA bus controller, etc. The 82C599 PCI controller provides
the bridge between PCI master/slave agent and the ISA/VESA standard
expansion bus; it arbitrates all the bus transactions between host CPU,
PCI agent, VESA device, and ISA device.(Which sounds to me like the PCI bus is attached to the VL bus, rather
than to the CPU, which will cause PCI performance degredation.)3) The FINALI-486 Chipset (Acer Labs: 10B9/4281) (8/27/95)
----------------------This is ALI's chipset for 486 systems, consisting of the M1487 and M1489
chips. It supports EDO RAM and all the different 486 CPUs, and has IDE,
a real-time clock, and a keyboard controller. I've no reports of
success with boards using this chipset, and ACER 486's which use the
board usually have slow cache controllers. Use CTCM to check your
board's performance.4) The Opti Chipset (Opti: 1045/4165) (8/27/95)
----------------Components: 82C822 (PCI functions)
82C895 (all other functions)This is Opti's chipset for 486-based machines. It's reported to work
well with OS/2, although it implements PCI using a VL-to-PCI bridge
instead of the other way around. Apparently this chipset will only
allow 1 32-bit burst transfer per bus arbitration cycle, which limits
throughput to 8 MB/s instead of (the maximum ideal transfer rate of) 132
MB/s. Boards which use this chipset are, therefore, to be avoided.5) The Saturn Family of Chipsets (Intel: 8086/32902) (8/27/95)
-----------------------------The Saturn family of chipsets is designed for use exclusively with 80486
and compatible processors, up to DX4s. They will, as of the latest
revision, work with the P24T Pentium Overdrive processor. Boards which
use them typically are of the combination ISA/PCI type, as I do not
believe the Saturn chipsets were designed to handle VL extensions.The Saturn chipset has been through three revisions, numbered (oddly
enough) 1, 2, and 4. Some brief comments on each:Rev. 1: Is now long-since discontinued. This chipset will only appear
on older motherboards (perhaps pre Jan. '94?), and should not
be on any motherboards of recent vintage. This chipset had
problems (unknown to me), and so was put through its first
revision and re-released.Rev. 2: Is still in wide use. This chipset has problems with cache
integrity during PCI to CPU burst mode operations, as well as
certain SCSI operations. Any board which uses this chipset
today will still have these problems. There are BIOS "fixes"
provided by various manufacturers, but what these usually do is
disable the high-performance options on the chipset. Rev. 2
was never 'fixed', and there is no such thing as a newer
release called rev. 2. Because of the bugs, however, a new
version of the Saturn chipset was released.Rev. 4: With this release of the Saturn chipset, Intel seems to have
finally fixed the problems with the earlier revisions. This
chipset (also called Saturn II) also supports all the green
features when used in combination with the right BIOS. It is
distinguished externally from its older cousins by the last two
letters on one of the three chips. Check for a 'ZX' to
positively identify the Saturn II chipset. This chipset, when
presented with a device which transfers 100 Mb/s, doesn't seem
to let the CPU run at all.6) The SIS chipset (Silicon Integrated Systems: 1039/4153) (9/4/95)
---------------Components: 85C496 and 85C497
SIS makes a separate chipset for 486-based boards which is commonly used
in systems which also have VL slots. Unfortunately, it sounds as though
the chipset implements PCI by bridging it to VL (instead of the other
way around), so PCI-based systems which have VL slots will suffer a
degredation of PCI performance. Still, however, boards manufactured by
AMI and Asus have been reported to work well with OS/2. There have been
five revisions of this chipset. A4 (the earliest one) supports IDE up
to mode 2 but apparently was not stable with caches on. B2 had
on-board IDE support but did not support mode 3 well. Revisions B3 and
later apparently work better. The varisous chipset revisions can be
identified by their labels:A4 Version chipset: SIS 496 MU, SIS 497 MW
B2 Version chipset: SIS 496 NU, SIS 497 NS
B3 Version chipset: SIS 496 NV, SIS 497 NS
B4 Version chipset: SIS 496 NV, SIS 497 NU
B4 Version chipset: SIS 496 OR, SIS 497 OTNone of these chipsets support PCI - PCI bridges, so that the Adaptec
3940 will not work with any motherboards which use this chipset.7) The VIA GMC chipset (Vendor unknown) (8/27/95)
--------------------This chipset includes the VIA VT82C486A-F with a built-in 8042 keyboard
controller and a VIA VT82C505-D chipset for the VESA to PCI bridge.
Specifically, the chips are as follows:82C486A - cache/memory controller + VLB to ISA bridge
82C482 - VLB to ISA bridga (why there are two I'm not sure)
82C483 - DRAM controller
VT82C505 PCI to VLB bridgeA board using this chipset has been unstable (even under DOS/Win), and
did not work with an Adaptec 2940 SCSI controller under OS/2 at all.
Boards based on this chipset are therefore to be avoided. I have,
however, had one report of success from someone using revision G of this
chipset, so it could be that the new revision fixes problems with older
rev's. Designers with whom I've corresponded indicate that improperly
designed boards which use this chipset may have unstable caches. In
addition, the cache controller reads the data into the cache SRAMs
first, then into the CPU, increasing latency and reducing throughput.
swaaye, nice info! But why don't I see UMC? 😉
I want to test a good 486 VLB only mobo, to see if it's any faster than a 486 mobo that uses PCI. I understand from reading old posts on Vogons that a good VLB board is better than most (if not all) PCI boards, in terms of video performance. I am beginning to doubt this notion, having seen my PCI Biostar score 12.5 on Pcpbench (default mode) with a Virge 325, and also having got this system stable at 200 MHz within Windows 98.
By avoiding the integrated IDE, using a CF device, using a copper cooler, using a good ATX PSU (with adapter), and hand picking a PCI VGA card, I experieced no problems with a 50 MHz bus speed on the PCI mobo, without the need to use a PCI divider.
IMHO, the VLB only solution has some "value" knocked off it with the apparent absense of EDO RAM support, and the scarcity of PS/2 support. And it sounds like getting a 50 MHz bus speed working correctly is error prone. However, if I can get Asus VLI-486SV2GX4 board to work well, then I will revise some of my potentially hasty and erroneous assumptions made above. 😉
Well VLB is literally a bus that comes right off of the 486 CPU so it is likely to be best. Especially when PCI on 486s doesn't have good busmaster support which is a PCI highlight over VLB. And this is mainly because PCI is most often connected to VLB.
However there's no doubt that there are better cards for PCI than VLB because VLB went away in 95 or so. VLB is not really compatible with Pentiums because it's so tightly related to 486.
@swaaye
Thanks for information! Probably you are right and most of the above chipsets are poor but not all! Personally I used to use Ali, UMC and VIA based 486 PCI motherboards. I encountered some PCI related problems only on VIA motherboard. UMC and ALI worked flawlessly. So I think that not all 486 PCI chipsets are bad - late behave properly. I guess that some have even better compatibility than modern chipsets when it comes to test old PCI cards. For example I noted that my two ET6000 PCI graphic cards work correctly on dusty 486 PCI 2.0 compliant motherboard but don't want to boot up on modern motherboards (Via and AMD chipset)!
I don't care about 486 PCI performance, because in this case memory bandwith is bottleneck. I have always treated 486 PCI chipsets as a gift that extended 486 market life and allowed me to use modern peripherals.
Regards! (:
@rg100
I like your way of thinking. We should retest this old hardware and abolish the myths! [:
Today I found a Cyrix 5x86-100 Chip wit 4x multiplier in a scrap lot. It runs fine at 133 MHz 😀
Speedsys comparison with Am5x86-133 on HOT-433 Mobo:
wrote:Today I found a Cyrix 5x86-100 Chip wit 4x multiplier in a scrap lot. It runs fine at 133 MHz 😀
Afaik not all Cyrix 5x86's even had the 4x multi, you should definitely keep it! 😉
@Tertium
Has your Cx5x86 133MHz arrived yet?
Regards! (;
wrote:@Tertium
Has your Cx5x86 133MHz arrived yet?
Regards! (;
I haven't requested shipping yet (and not in a hurry either, sorry!).
I'll report back when it arrives though, ok?
All I remember is I'm getting a 3.6v variant (there were supposedly also 3.7v parts).
I too have had few complaints w.r.t UMC's handling of PCI w/486 motherboards. For years I have been using a 3-slot PCI UMC-based 486 with PCI graphics, PCI SCSI, and PCI networking (Matrox G200, Adaptec 2940U2W, 3Com 3c905-TX-M 10/100Base-TX, respectively) in Windows NT 4.0 without incident. The chipsets are UM8881F (9633-EYT) and UM8886BF (UM9631-FXO) on a Biostar MB-8433UUD v3.0 motherboard w/Award 4.50PG BIOS (26 Mar. 1996). The system is also stable in Win95/98 and Win2000.
Similarly, on a PC Chips M919 v3.4, with chipsets marked UM8881F (9651-EYA) and UM8886BF (UM9703-FXA) and an AMI BIOS (5 June 1996), PCI performance and stability have been flawless in Win95/98/NT4. Win2000 seems to have issues with the Adaptec 2940U2W SCSI card though.
All systems were tested with 0 wait states for RAM and 2-1-1-1 (or 2-1-2) cache timings over the period of at least 3 years of continuous running. EDO and FPM memory is stable for both systems. Benchmark results were posted elsewhere.
Does anyone know how to determine which PCI revision exists on 486-era motherboards? Check for 3.3V or 5.0V on PCI pin A10? Wiki lists PCI 2.1 as coming out around in 06-1995. Both the chipsets and BIOS for the two above mentioned motherboards are about a year older than this.
Speedsys' PCI info has a PCI 2.10 spec listing for these, but this may just be a standard box in Speedsys (press -I- after Speedsys finishes memory throughput checking). Speedsys also says PCI 2.10 for my year 2002 PIII motherboard.
@BastlerMike
What RAM wait states were you using? What about cache timing?
Did you determine if your 5x86-100/133 was stable in Windows 9X/NT or was it only tested with a DOS boot disk and Speedsys? A lot of times a system can appear stable in DOS but fail miserably with Windows.
Your results seem really slow for a Cyrix 5x86 at 133 Mhz. This is what I get for a Cyrix 5x86-120,
Speedsys:
Benchmark number: 65.49
L1: 172.98 MB/s
L2: 67.92 MB/s
Memory throughput: 47.97 MB/s
Cachechk v4
L1: 246.3 MB/s
L2: 95.8 MB/s
RAM: 55.1 MB/s
RAM access, read: 76 ns
RAM access, write: 51 ns
120.5 Mhz
This was on a Biostar MB-8433UUD v3.0, but I achieved the same cachechk results on a Shuttle HOT-433 with the Cyrix 5x86-120. You can refer to page 6 of the following posting for further information on this,
486 mobo + 586 chip
@udam_u
Did you ever retest for speedsys and cachechk results on your overclocked Cyrix 5x86 @ 150 Mhz?
I was unsuccessful with this overclock operation, however I did not give it much time. I spent more time with the 66 Mhz FSB setting and getting it to run at 133 Mhz w/2x, unfortunately it will not. It will run in DOS at 60 Mhz x2 (120 Mhz), but this kinda defeats the point. I tried to
@Tetrium
I anxiously await your 'official' 5x86-133 test results.
wrote:@Tetrium
I anxiously await your 'official' 5x86-133 test results.
It might simply disappear in my cupboard, I wouldn't wanna scratch it 😜
Maybe I'll put it right next to that AMD DX4-90 which I can't guarantee to be a remark anyway but atleast was cheap 😜
@Tetrium thanks - I will be waiting for info from you. I have to admit you are very patient. If I were you I would request shipping immediately. ^^
I wonder if this cpu is good overclocker - I would expect overclocking to150MHz without need to increase voltage above 4V. (;
@feipoa Unfortunatelly I haven't got opportunity to retest this system because of lack hdd. Recently I had some cash but I encountered another occasions (CT1600, CT3980, ET6000, Rendition V2200 AGP) and currently my piggybank is again empty. Anyway I think that I will be able to buy CF card and retest cx5x86 system in April (because of my birthday he he he). In my opinion 2x66MHz is the best configuration for this CPU. I obtained satisfactory system stability by increasing voltage to 5V and using efficient copper socketA cooler. What type of cooler did you use?
Regards! (:
